CN117810333A - Light emitting diode and light emitting device - Google Patents

Abstract

The present application provides a light-emitting diode and a light-emitting device. The light-emitting diode of the present application includes doping a first N-type impurity in a first semiconductor layer, and the first N-type impurity has a distance of 200 nm to 400 nm from the bottom surface of the active layer. A point A with a concentration of 2E17/cm ³ . The above-mentioned first N-type impurity is Te. Since Te itself has good high-temperature characteristics, its concentration is more stable at high temperatures. At the same time, due to the metal-like characteristics of Te, its number of atoms is relatively large and its mobility is low. Based on the above reasons, doping Te in the first semiconductor layer can effectively inhibit the migration of dopants in the first semiconductor layer to the active layer, improve the crystal quality of the active layer, and at the same time ensure that the first semiconductor layer moves to the active layer. The layer provides sufficient electrons to ensure the brightness of the light-emitting diode.

Description

A kind of light-emitting diode and light-emitting device

Technical field

The present invention relates to the technical field of semiconductor devices and apparatuses, and in particular to a light emitting diode and a light emitting apparatus.

Background technique

Light Emitting Diode (LED) has the advantages of high luminous intensity, high efficiency, small size, and long service life, and is considered to be one of the most promising light sources currently. In recent years, LEDs have been widely used in daily life, such as lighting, signal displays, backlights, car lights, and large-screen displays. At the same time, these applications have also put forward higher requirements for the brightness and luminous efficiency of LEDs.

The light-emitting diode realizes at least providing electrons or holes respectively through n-type doping or p-type doping of the first type semiconductor layer and the second type semiconductor layer, and the electrons and holes radiate and recombine to emit light in the active layer. The recombination efficiency in epitaxial structure MQW is affected by the position of the luminescent recombination center, the efficiency of electrons and holes, etc. The mobility of electrons is relatively fast, which affects the efficiency of recombination of electrons and holes. On the other hand, in order to increase sufficient electrons and holes, the first type semiconductor layer and the second type semiconductor layer need to reach a higher doping concentration. Due to the diffusion effect and memory effect of n-type and p-type dopants, n-type and p-type dopants easily diffuse into the active layer, affecting the crystal quality of the active layer, thereby affecting the luminous brightness of the light-emitting diode.

Contents of the invention

In view of the contradiction between the electron and hole recombination efficiency of a light emitting diode and the doping concentration of n-type and p-type dopants in the prior art, the present invention provides a light emitting diode and a light emitting device to solve one or more of the above problems.

One embodiment of the present application provides a light-emitting diode, which at least includes:

Semiconductor epitaxial stack, including a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence; the active layer includes alternately stacked well layers and barrier layers, and the active layer faces the second semiconductor layer One side of the layer is the upper surface, and the side opposite to the upper surface and facing the first semiconductor layer is the bottom surface;

Wherein, the first semiconductor layer includes a first N-type impurity, the first N-type impurity has a first concentration profile, the first concentration profile has an A point with a concentration of 2E17/cm ³ , and the A point The distance from the bottom surface of the active layer ranges from 200 nm to 400 nm.

Another embodiment of the present application provides a light-emitting device, which includes the light-emitting diode provided by the present application.

As mentioned above, the light-emitting diode and light-emitting device of the present application have the following beneficial effects:

The light-emitting diode of the present application includes a first N-type impurity doped in the first semiconductor layer, and the first N-type impurity has a point A with a concentration of 2E17/cm ³ within a range of 200nm to 400nm from the bottom surface of the active layer. The above-mentioned first N-type impurity is Te. Since Te itself has good high-temperature characteristics, its concentration is more stable at high temperatures. At the same time, due to the metal-like characteristics of Te, the number of its atoms is relatively large and the mobility is low. Based on the above reasons, doping Te in the first semiconductor layer can effectively inhibit the migration of dopants in the first semiconductor layer to the active layer, improve the crystal quality of the active layer, and at the same time ensure that the first semiconductor layer provides sufficient electrons to the active layer, thereby ensuring the luminous brightness of the light-emitting diode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic structural diagram of an epitaxial structure of a light-emitting diode provided in Embodiment 1 of the present application.

FIG. 2 shows a schematic structural diagram of a light-emitting diode provided in Embodiment 1 of the present invention.

FIG. 3 is a schematic top view of the light emitting diode shown in FIG. 2 .

FIG. 4 shows a schematic structural diagram of a light-emitting device provided in Embodiment 2 of the present invention.

Component label description

100. Growth substrate; 101. First semiconductor layer; 1011. N-type ohmic contact layer; 1012. First window layer; 1013. First covering layer; 102. Active layer; 1021. Barrier layer; 1022. Well layer; 103, second semiconductor layer; 1031, second covering layer; 1032, transition layer; 1033, P-type ohmic contact layer; 104, dielectric layer; 105 bonding layer; 106 substrate; 107, first electrode; 1071, Extension strip; 108, back gold layer; 109, insulating protective layer; 110, metal layer; 200, light-emitting device; 201, circuit substrate; 202, light-emitting diode.

Detailed ways

The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

In the prior art, the N-type layer in the AlGaInP series light-emitting diode is usually doped with Si, which can provide electrons for radiative recombination. However, due to the diffusion effect and memory effect of Si, it is easy to diffuse into the active layer, affecting the crystal quality of the active layer, thereby affecting the brightness of the light-emitting diode. In view of the above problems, the present application provides a light-emitting diode, which at least includes:

Semiconductor epitaxial stack, including a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence; the active layer includes alternately stacked well layers and barrier layers, and the active layer faces the second semiconductor layer One side of the layer is the upper surface, and the side opposite to the upper surface and facing the first semiconductor layer is the bottom surface;

Wherein, the first semiconductor layer includes a first N-type impurity, the first N-type impurity has a first concentration profile, the first concentration profile has an A point with a concentration of 2E17/cm ³ , and the A point The distance from the bottom surface of the active layer ranges from 200 nm to 400 nm.

The above-mentioned first N-type impurity selects element Te, which has better high-temperature performance, so its concentration is more stable and its mobility is low at high temperatures. Based on the above reasons, the first N-type impurity can effectively inhibit the migration of dopants in the first semiconductor layer to the active layer, improve the crystal quality of the active layer, and at the same time ensure that the first semiconductor layer provides sufficient supply to the active layer. of electrons, thereby ensuring the brightness of the light-emitting diode.

Optionally, the first concentration profile ranges from 5E17/cm ³ to 4E18/cm ³ . This concentration can effectively maintain the stability of the first N-type impurity and ensure that the impurities in the first semiconductor layer will not enter the active layer.

Optionally, the first N-type impurity is Te. Te has good high-temperature stability and memory. At the same time, because it is a metal-like element with large atoms and low mobility, it can effectively suppress the diffusion of impurities in the first semiconductor layer to the active layer and improve the stability of the active layer. Crystal quality, improve light emission effect.

Optionally, the first semiconductor layer further includes a second N-type impurity, the second N-type impurity has a second concentration profile, and the second concentration profile has a point B with a concentration of 2E17/cm ³ , so The distance between point B and the bottom surface of the active layer is greater than 50 nm. The doping concentration and doping depth of the second N-type impurity can ensure that sufficient electrons are provided to the active layer to achieve luminescence of the active layer. At the same time, the first N-type impurity will not diffuse into the active layer under the action of the first N-type impurity, improving the efficiency of the active layer. Crystal quality of the active layer.

Optionally, the second concentration profile ranges from 2E17/cm ³ to 4E18/cm ³ . The doping concentration of the second N-type impurity ensures that sufficient electrons are provided to the active layer to achieve luminescence of the active layer.

Optionally, the second N-type impurity is Si. Si can provide enough electrons, and its mobility is fast, and it can provide enough electrons to the active layer to achieve recombination of electrons and holes to achieve light emission.

Optionally, the first semiconductor layer includes a first covering layer, wherein the first covering layer includes the second N-type impurity. The first covering layer includes the above-mentioned Si impurity, and thus can provide sufficient electrons to the active layer.

Optionally, the doping thickness of the second N-type impurity is 1/3˜2/3 of the thickness of the first covering layer. This doping thickness can ensure that it provides sufficient electrons to the active layer while ensuring that they will not diffuse into the active layer and ensure the crystal quality of the active layer.

Optionally, the first semiconductor layer further includes a first window layer located on a side of the first cladding layer away from the active layer, and the first window layer contains the first N-type impurity. The first N-type impurity in the first window layer cooperates with the second N-type impurity in the first covering layer to ensure that the active layer obtains enough electrons and prevents impurities from diffusing into the active layer.

Optionally, the material of the first covering layer and the first window layer is AlGaInP or AlInP.

Optionally, the light-emitting diode further comprises p-type impurities, the p-type impurities are located in the second semiconductor layer, and the third concentration profile comprises a point B with a concentration of 1E17/cm ³ , the distance from the point B to the upper surface of the active layer is d2, and the range of d2 is 40 to 400 nm. The doping range and doping depth of the p-type impurities in the second semiconductor layer can ensure that it provides sufficient holes to the active layer to achieve recombination of electrons and holes to achieve light emission.

Optionally, the second type semiconductor layer includes a second covering layer, and the second covering layer contains the P-type impurity.

Optionally, the p-type dopant is Mg, Zn, Ca, Sr or Ba.

Optionally, the material of the second covering layer is AlGaInP or AlInP, and the doping concentration of the P-type impurity in the second covering layer is greater than 1E17/cm ³ .

Optionally, the number of cycles of the active layer ranges from 2 to 100. The period number of the active layer is set so that it can effectively obtain enough holes and electrons to achieve recombination of the two and ensure effective light extraction.

Optionally, the thickness of the well layer of the active layer is 2 nm to 25 nm, and the thickness of the barrier layer is 2 nm to 25 nm.

Optionally, the active layer radiates light with a wavelength of 550 nm to 950 nm.

Another embodiment of the present invention provides a light-emitting device, which includes the light-emitting diode provided in this application. The light-emitting device includes the light-emitting diode of the present application, so it can achieve good light-emitting effect.

Embodiment 1

This embodiment provides a light-emitting diode. The light-emitting diode at least includes a semiconductor epitaxial stack, including a first semiconductor layer 101, an active layer 102 and a second semiconductor layer 103 stacked in sequence; the active layer 102 includes an alternately stacked Well layer 1022 and barrier layer 1021, the side of the active layer 102 facing the second semiconductor layer 103 is the upper surface, and the side opposite to the upper surface and facing the first semiconductor layer 101 is the bottom surface. . In an optional embodiment, the above-mentioned semiconductor epitaxial stack is an AlGaInP-based epitaxial structure, and one side of the above-mentioned first semiconductor layer 101 is the light-emitting side. The first semiconductor layer 101 is optionally an N-type AlInP layer or an AlGaInP layer for providing electrons. . The N-type AlInP layer or AlGaInP layer is doped with n-type impurities to provide electrons. The n-type impurities can be, for example, Si, Ge, Sn, Se, and Te. The second semiconductor layer 103 is optionally a P-type AlInP layer or an AlGaInP layer, and holes are provided by doping P-type impurities, which may be Mg, Zn, Ca, Sr, C, Ba, etc. In this embodiment, the P-type impurity is preferably Mg or C. The active layer 102 is a multiple quantum well layer 1022, for example, it can be a multiple quantum well layer 1022 formed of AlGaInP/AlInP. The number of cycles of the active layer 102 is 2 to 100, and the thickness of the well layer 1022 is 2 nm to 25 nm. The thickness of the barrier layer 1021 is 2 nm to 25 nm. The thickness of the well layer 1022 and the barrier layer 1021 may be the same or different, and may be set according to actual needs. The active layer 102 radiates light with a wavelength of 550 nm to 950 nm.

In an optional embodiment, the first semiconductor layer 101 includes a first N-type impurity. The first N-type impurity has a first concentration profile. The first concentration profile has a point A with a concentration of 2E17/cm ³ . Point A The distance from the bottom surface of the active layer 102 is between 200 nm and 400 nm.

Specifically, as shown in FIG. 1 , the above-mentioned semiconductor epitaxial layer is formed on the growth substrate 100 , where the first semiconductor layer 101 at least includes an N-type ohmic contact layer 1011 , a first window layer 1012 and a first covering layer 1013 . The N-type ohmic contact layer 1011 is used to form ohmic contact with the electrode material when forming the electrode to reduce contact resistance. The first window layer 1012 is formed as a layer, usually an AlGaInP layer or an AlInP layer. The first window layer 1012 is formed between the first covering layer 1013 and the N-type ohmic contact layer 1011. The first window layer 1012 serves as a light emitting diode. Shiny surface. Optionally, the first window layer 1012 includes the above-mentioned first N-type impurity, the first N-type impurity is Te, which has the above-mentioned first concentration profile, and the first concentration profile is between 5E17/cm ³ and 4E18/cm ³ . The first concentration profile has a point A with a concentration of 2E17/cm ³ . The point A is located in the first window layer 1012 and within a depth range of 200 nm to 400 nm from the bottom surface of the active layer 102 . Optionally, the distance between the above-mentioned point A and the bottom surface of the active layer 102 is 250nm, 300nm, or 350nm. Because Te itself has good high-temperature properties, its concentration is more stable at high temperatures. At the same time, due to the metal-like properties of Te, its number of atoms is relatively large and its mobility is low. Based on the above reasons, doping Te in the first semiconductor layer 101 can effectively inhibit the migration of dopants in the first semiconductor layer 101 to the active layer 102, improve the crystal quality of the active layer 102, and ensure that the first semiconductor layer 101 Sufficient electrons are provided to the active layer 102, thereby ensuring the brightness of the light-emitting diode.

In an optional embodiment, the first semiconductor layer 101 further includes a second N-type impurity, and the second N-type impurity has a second concentration profile. Optionally, the above-mentioned second concentration profile is between 2E17/cm ³ and 4E18/cm ³ , wherein the second concentration profile has a point B with a concentration of 2E17/cm ³ , and the distance between the point B and the bottom surface of the active layer 102 is greater than 50 nm, for example, between 50 nm and 100 nm, or between 50 nm and 60 nm. Optionally, the first cladding layer 1013 contains the second N-type impurity, that is, point B is located in a depth range greater than 50 nm from the bottom surface of the active layer 102 in the first cladding layer 1013. Further, point B The doping thickness is 1/3˜2/3 of the thickness of the first covering layer 1013 . Optionally, the second N-type impurity is Si. Due to the fast migration rate of Si, it can ensure sufficient electron supply, ensure the light extraction rate of the light-emitting diode, and at the same time reduce the voltage of the light-emitting diode. At the same time, due to the above-mentioned Te doping, on the basis of ensuring that the first semiconductor layer 101 provides sufficient electrons, the problem of Si atoms diffusing to the active layer 102 will not occur, improving the crystal quality of the active layer 102 to ensure that the light-emitting diode The lighting effect.

Also as shown in FIG. 1 , the second semiconductor layer 103 includes a second cladding layer 1031 , a transition layer 1032 and a P-type ohmic contact layer 1033 stacked in sequence, where the second cladding layer 1031 is adjacent to the active layer 102 and the P-type ohmic contact layer Layer 1033 is formed on a side of the second covering layer 1031 away from the active layer 102, and a transition layer 1032 is formed between the second covering layer 1031 and the P-type ohmic contact. The second semiconductor layer 103 contains p-type impurities, and the p-type impurities are Mg, Zn, Ca, Sr or Ba. The P-type impurity includes a third concentration profile. In order to ensure that sufficient holes are provided to the active layer 102, the third concentration profile is greater than 1E17/cm ³ , wherein the third concentration profile has a point B with a concentration of 1E17/cm ³ , the distance from point B to the upper surface of the active layer 102 is d2, and the range of d2 is 40-400 nm. In the depth range where the distance from the upper surface of the active layer 102 is less than d2, the concentration of p-type impurities in the second covering layer 1031 is lower than 1E17/cm ³ , thereby preventing the p-type impurities from diffusing into the active layer 102. Affects the crystal quality of the active layer 102 . Optionally, the above-mentioned second covering layer 1031 is an AlInP material layer, thereby reducing light absorption of the second covering layer 1031 and improving the luminous brightness of the light-emitting diode. In some optional embodiments, the second covering layer 1031 may be a single-layer structure or a multi-layer structure. In this embodiment, it may be a multi-layer structure.

Referring to FIG2 , the light-emitting diode of this embodiment bonds the epitaxial structure shown in FIG1 to the substrate 106 from the side of the second semiconductor layer 103, and removes the growth substrate 100, and the side of the exposed first semiconductor layer 101 is the light-emitting side. A bonding layer 105 is formed between the epitaxial structure and the substrate 106, and the bonding layer 105 bonds the epitaxial structure to the substrate 106. A dielectric layer 104 is also formed between the bonding layer 105 and the epitaxial structure, and a through hole is formed in the dielectric layer 104. A metal layer 110 can be formed in the through hole and on the side of the dielectric layer 104 away from the epitaxial structure, and the metal layer 110 in the through hole is connected to the P-type ohmic contact layer 1033 in the second semiconductor layer 103, thereby reducing the contact resistance. Optionally, a current expansion layer can also be formed between the p-type ohmic contact and the p-type cover layer to increase the lateral expansion of the current and improve the light-emitting effect. The dielectric layer 104 may be a single-layer structure formed by one of SiO ₂ , SiN, SiON, TiO ₂ , etc., or a multi-layer structure formed by a combination of any of them, and may optionally be a DBR structure with a reflective effect, such as a DBR structure formed by SiO ₂ and TiO _2. The metal layer 110 forms a metal mirror, which together with the dielectric layer 104 can form a total reflection structure, increase the reflection of the light radiated by the active layer 102, and enhance the light emitting effect of the light emitting diode. A back gold layer 108 is formed on the other side of the substrate 106 opposite to the epitaxial structure, and the back gold layer 108 can be used as a second electrode electrically connected to the second semiconductor layer 103. As shown in FIG. 2 , the light emitting diode of this embodiment also includes a first electrode 107 formed above the first semiconductor layer 101, and the first electrode 107 is connected to an N-type ohmic contact to reduce contact resistance. Referring to FIG. 3 , in order to increase the lateral expansion of the current, an extension bar 1071 of the first electrode 107 is also formed above the first semiconductor layer 101, and the extension bar 1071 can be formed into a finger shape as shown in FIG. 3 .

Referring to Figure 2, in order to further increase the light extraction effect of the light-emitting diode, in this embodiment, after the first electrode 107 is formed, the surface of the first semiconductor layer 101 other than the first electrode 107 is roughened to form a roughened surface. This increases the light extraction rate. At the same time, an insulating protective layer 109 is also formed on the exposed surface of the light-emitting diode to protect the light-emitting diode from damage by external water vapor and impurities.

Embodiment 2

This embodiment provides a light-emitting device. As shown in Figure 4, the light-emitting device 200 includes a circuit substrate 201 and at least one light-emitting diode 202 fixed to the circuit substrate 201. The light-emitting diode includes the light-emitting diode provided in the first embodiment of the present application. led. Because the light-emitting device includes the light-emitting diode provided in Embodiment 1, it has good light emitting effect and has better reliability.

The above embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (18)

1. A light emitting diode comprising at least:

a semiconductor epitaxial stack including a first semiconductor layer, an active layer, and a second semiconductor layer stacked in this order; the active layer includes well layers and barrier layers alternately stacked, a face of the active layer facing the second semiconductor layer being an upper surface, a face disposed opposite to the upper surface and facing the first semiconductor layer being a bottom surface;

wherein the first semiconductor layer comprises a first N-type impurity having a first concentration profile with a concentration of 2E17/cm ³ The distance between the point A and the bottom surface of the active layer is 200-400 nm.

2. The led of claim 1, wherein the first concentration profile is between

5E17/cm ³ ～4E18/cm ³ 。

3. The light emitting diode of claim 1 or 2, wherein the first N-type impurity is Te.

4. The led of claim 1, wherein the first semiconductor layer further comprises a second N-type impurity having a second concentration profile having a concentration of 2E17/cm ³ B of (2)

And a point, wherein the distance between the point B and the bottom surface of the active layer is greater than 50nm.

5. The led of claim 1 or 4, wherein the second concentration profile is between

2E17/cm ³ ～4E18/cm ³ 。

6. The led of claim 4, wherein the second N-type impurity is Si.

7. The light emitting diode of claim 1, wherein the first semiconductor layer comprises a first cap layer comprising the second N-type impurity.

8. The led of claim 7, wherein the second N-type impurity has a doping thickness of 1/3 to 2/3 of the thickness of the first cap layer.

9. The light emitting diode of claim 7, wherein the first semiconductor layer further comprises a first window layer on a side of the first cap layer remote from the active layer, the first window layer comprising the first N-type impurity.

10. The light emitting diode of claim 9, wherein the material of the first cladding layer and the first window layer is AlGaInP or AlInP.

11. The led of claim 1, further comprising a P-type impurity in the second semiconductor layer comprising a third concentration profile having a concentration of 1E17/cm ³ The distance from the B point to the upper surface of the active layer is d2, and the d2 is in the range of 40-400 nm.

12. The light emitting diode of claim 11, wherein the second type semiconductor layer comprises a second cap layer, the second cap layer comprising the P-type impurity.

13. The led of claim 12, wherein the p-type impurity is Mg, zn, ca, sr or Ba.

14. The led of claim 12, wherein the second cladding layer is AlGaInP or AlInP, and the P-type impurity has a doping concentration in the second cladding layer of greater than 1E17/cm ³ 。

15. The light-emitting diode according to claim 1, wherein the number of cycles of the active layer is 2 to 100.

16. The light-emitting diode according to claim 1, wherein the well layer of the active layer has a thickness of 2nm to 25nm, and the barrier layer has a thickness of 2nm to 25nm.

17. The light-emitting diode according to claim 1, wherein the active layer radiates light having a wavelength of 550nm to 950 nm.

18. A light-emitting device comprising the light-emitting diode according to any one of claims 1 to 17.